package task;

import java.util.Scanner;

public class Task4_5 {
    public static void main(String[] args) {
        int counter = 0;
        System.out.println("输入多少个数字");
        Scanner input = new Scanner(System.in);
        int n = input.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < a.length; i++) {
            a[i] = input.nextInt();
        }
        int sum = a[0];
        for (int i = 1; i < a.length; i++) {
            sum = sum ^ a[i];//相同的数字异或为0输出不同的数字

        }
        System.out.println(sum);
    }


}
